the only rule is work

In the print lab at City College, I spied, half hidden under a clock,
a copy of Corita Kent's "Artful Rules for Work and Life,"
developed for the Art Department of Immaculate Heart College, where
she taught for over twenty years.

Her "rules" are worth quoting in full.

Rule 1 Find a place you trust and then try trusting it for a while.

Rule 2 General duties of a student: Pull everything out of your teacher.
Pull everything out of your fellow students.

Rule 3 General duties of a teacher: Pull everything out of your students.

Rule 4 Consider everything an experiment.

Rule 5 Be self-disciplined. This means finding someone wise or smart and
choosing to follow them. To be disciplined is to follow in a good way.
To be self-disciplined is to follow in a better way.

Rule 6 Nothing is a mistake. There's no win and no fail. There's only make.

Rule 7 The only rule is work. If you work it will lead to something. It's
the people who do all of the work all the time who eventually catch on
to things.

Rule 8 Don't try to create and analyse at the same time. They're different
processes.

Rule 9 Be happy whenever you can manage it. Enjoy yourself. It's lighter
than you think.

Rule 10 "We're breaking all of the rules. Even our own rules. And how do
we do that? By leaving plenty of room for x quantities." —John
Cage.

Helpful Hints: Always be around. Come or go to everything. Always go to classes.
Read anything you can get your hands on. Look at movies carefully.
Often save everything — it might come in handy later.

We can take this elsewhere, but TOC is a concept around operations management: how one runs a production facility, projects, the supply chain, and sales and marketing. I've seen "design constraint" discussions, which are very interesting too - but I think there are some differences in the approach. That said, in both cases, the constraint(s) cause you to focus your efforts.